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چکیده
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Today, waterjets and their types are widely used in various industries because of their unique ability in cutting and machining. Due to the widespread use of waterjets in various industries and the lack of attention to the efficiency and improvement of the cutting and machining process of waterjets, the importance of modeling the waterjet cutting process and determining the key parameters for cutting improvement becomes apparent. High pressure water supply unit and cutter-head are the two main parts of waterjet devices. Abrasive waterjets (AWJ) are one of the most common types of waterjets. Particle waterjet is a type of abrasive waterjet in which large particles with low concentration are used instead of smaller size and more abundance particles. In this research, rock cutting by particle waterjet has been simulated using smooth particle hydrodynamics-finite element method (SPH-FEM) with the help of LS-DYNA software. Before obtaining the results, in computational fluid dynamics modeling of the problem, grid independence test, computational time step and validation of the results with previous studies have been performed. The effect of various parameters such as velocity, dwell time, feeding rate and diameter of abrasive particles as well as impact angle on the cutting phenomenon of different rock samples such as siltstone, sandstone and marble has been investigated. Numerical results reveal that by increasing the velocity and dwell time, the two-phase jet has more momentum and energy and significantly improves rock cutting. In addition, by increasing the volume concentration of abrasives to 3%, the depth and volume of cutting in rocks increased with a gentler slope, and after that, no clear improvement was observed. The results showed that by increasing the diameter of abrasive particles to a certain amount, heavier particles with less number can play a more effective role in cutting rocks compared to lighter particles with more number. Also, jet impact angles are suggested to achieve maximum effect in cutting all kinds of rocks. In general, it can be concluded that by using high-velocity particle waterjet, it is possible to cut all kinds of rock samples, especially decorative and mineral rocks, with high precision.
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